[In search of strategies for preventing brain damage as a sequela of bacterial meningitis]

Multiplication of bacteria within the central nervous system compartment triggers a host response with an overshooting inflammatory reaction which leads to brain parenchyma damage. Some of the inflammatory and neurotoxic mediators involved in the processes leading to neuronal injury during bacterial meningitis have been identified in recent years. As a result, the therapeutic approach to the disease has widened from eradication of the bacterial pathogen with antibiotics to attenuation of the detrimental effects of host defences. Corticosteroids represent an example of the adjuvant therapeutic strategies aimed at downmodulating excessive inflammation in the infected central nervous system. Pathophysiological concepts derived from an experimental rat model of bacterial meningitis revealed possible therapeutic strategies for prevention of brain damage. The insights gained led to the evaluation of new therapeutic modalities such as anticytokine agents, matrix metalloproteinase inhibitors, antioxidants, and antagonists of endothelin and glutamate. Bacterial meningitis is still associated with persistent neurological sequelae in approximately one third of surviving patients. Future research in the model will evaluate whether the neuroprotective agents identified so far have the potential to attenuate learning disabilities as a long-term consequence of bacterial meningitis.

Fluoroquinolones in the Treatment of Meningitis

The continuous increase of resistant pathogens causing meningitis has limited the efficacy of standard therapeutic regimens. Due to their excellent activity in vitro and their good penetration into the cerebrospinal fluid (CSF), fluoroquinolones appear promising for the treatment of meningitis caused by gram-negative microorganisms, ie, Neisseria meningitidis and nosocomial gram-negative bacilli. The newer fluoroquinolones (moxifloxacin, gemifloxacin, gatifloxacin, and garenoxacin) have excellent activity against gram-positive microorganisms. Studies in animal models and limited clinical data indicate that they may play a future role in the treatment of pneumococcal meningitis. Analysis of pharmacodynamic parameters suggests that CSF concentrations that produce a C(peak)/minimal bactericidal concentration (MBC) ratio of at least 5 and concentrations above the MBC during the entire dosing interval are a prerequisite for maximal bactericidal activity in meningitis. Of interest, newer fluoroquinolones act synergistically with vancomycin and beta-lactam antibiotics (ceftriaxone, cefotaxime, meropenem) against penicillin-resistant pneumococci in experimental rabbit meningitis, potentially providing a new therapeutic strategy. Clinical trials are needed to further explore the usefulness of quinolones as single agents or in combination with other drugs in the therapy of pneumococcal meningitis.

Mechanisms of brain injury in bacterial meningitis: workshop summary

Morbidity and mortality associated with bacterial meningitis remain high, although antibiotic therapy has improved during recent decades. The major intracranial complications of bacterial meningitis are cerebrovascular arterial and venous involvement, brain edema, and hydrocephalus with a subsequent increase of intracranial pressure. Experiments in animal models and cell culture systems have focused on the pathogenesis and pathophysiology of bacterial meningitis in an attempt to identify the bacterial and/or host factors responsible for brain injury during the course of infection. An international workshop entitled "Bacterial Meningitis: Mechanisms of Brain Injury" was organized by the Department of Neurology at the University of Munich and was held in Eibsee, Germany, in June 1993. This conference provided a forum for the exchange of current information on bacterial meningitis, including data on the clinical spectrum of complications, the associated morphological alterations, the role of soluble inflammatory mediators (in particular cytokines) and of leukocyte-endothelial cell interactions in tissue injury, and the molecular mechanisms of neuronal injury, with potential mediators such as reactive oxygen species, reactive nitrogen species, and excitatory amino acids. It is hoped that a better understanding of the pathophysiological events that take place during bacterial meningitis will lead to the development of new therapeutic regimens.

Principles in the treatment of bacterial meningitis

The pathophysiologic aspects of bacterial meningitis impose some specific requirements on successful antimicrobial therapy of this disease. Because infections of the subarachnoid space rapidly produce destruction of the brain tissue, treatment must be instituted as early as possible. In the subarachnoid space, efficient host defense mechanisms are absent, particularly at the start of the infection, and therefore antibiotics have to produce a bactericidal effect to eliminate the microorganisms. As animal studies indicate, only drug concentrations 20- to 100-fold higher than the minimal bactericidal concentration are effective in vivo. Because penetration of antibiotics to the site of infection is limited by the blood-brain barrier, the high cerebrospinal fluid concentrations necessary to kill the bacteria may be difficult to achieve and therapy may be limited by toxicity. Even with optimal antibiotic therapy, the morbidity and mortality remain high, and new therapeutic interventions are necessary and should be aimed at modifying selective components of the inflammatory process.

Selective increases in regional brain glucocorticoid: a novel effect of chronic alcohol

The hypothalamo-pituitary-adrenal axis shows functional changes in alcoholics, with raised glucocorticoid release during alcohol intake and during the initial phase of alcohol withdrawal. Raised glucocorticoid concentrations are known to cause neuronal damage after withdrawal from chronic alcohol consumption and in other conditions. The hypothesis for these studies was that chronic alcohol treatment would have differential effects on corticosterone concentrations in plasma and in brain regions. Effects of chronic alcohol and withdrawal on regional brain corticosterone concentrations were examined using a range of standard chronic alcohol treatments in two strains of mice and in rats. Corticosterone was measured by radioimmunoassay and the identity of the corticosterone extracted from brain was verified by high performance liquid chromatography and mass spectrometry. Withdrawal from long term (3 weeks to 8 months) alcohol consumption induced prolonged increases in glucocorticoid concentrations in specific regions of rodent brain, while plasma concentrations remained unchanged. This effect was seen after alcohol administration via drinking fluid or by liquid diet, in both mice and rats and in both genders. Shorter alcohol treatments did not show the selective effect on brain glucocorticoid levels. During the alcohol consumption the regional brain corticosterone concentrations paralleled the plasma concentrations. Type II glucocorticoid receptor availability in prefrontal cortex was decreased after withdrawal from chronic alcohol consumption and nuclear localization of glucocorticoid receptors was increased, a pattern that would be predicted from enhanced glucocorticoid type II receptor activation. This novel observation of prolonged selective increases in brain glucocorticoid activity could explain important consequences of long term alcohol consumption, including memory loss, dependence and lack of hypothalamo-pituitary responsiveness. Local changes in brain glucocorticoid levels may also need to be considered in the genesis of other mental disorders and could form a potential new therapeutic target.

Marked improvement in nail psoriasis during treatment with adalimumab

BACKGROUND: Nail involvement is known as a common finding in psoriatic patients and represents a significant impact on patients' quality of life. The treatment of nail psoriasis is often challenging, and there is a need for new therapeutic options. Biologicals effective in the treatment of moderate to severe chronic plaque psoriasis may represent a new therapeutic modality for this disease. Adalimumab is a fully human IgG1 monoclonal antibody that binds to tumor necrosis factor alpha with high affinity and specificity. OBSERVATIONS: We report two cases of rapid improvement in nail psoriasis under adalimumab monotherapy with maintained effectiveness despite intermittent treatment as well as long remission after therapy discontinuation. CONCLUSION: The marked improvement of our two cases indicates that adalimumab may also help ameliorate nail psoriasis and warrants further controlled studies to establish the effectiveness and therapeutic regimes.

[Towards the Swiss systemic lupus erythematosus cohort study (SSCS)]

Systemic lupus erythematosus (SLE) is a rare disease mainly affecting women of childbearing age. It is characterized by a very large spectrum of clinical manifestations accompanied by prototypic abnormalities of the immune system. While recent advances in therapeutic approaches have taken place, SLE still has a profound impact on the quality of life and life expectancy of affected persons. The Swiss cohort for longitudinally studying SLE named SSCS responds to the necessity of better understanding the history of the disease, the mechanisms involved in its pathogenesis, to identify and apply new therapeutic and prevention strategies, as well as to analyze the impact that SLE has at the social and personal levels in Switzerland. SSCS is a tool to be used by all researchers interested to provide answers to the many open questions in SLE.

Taurolidine in the prevention and therapy of lung metastases

OBJECTIVE: During surgery for colon carcinoma, tumour cells may spread into the blood and may lead to the development of distant metastases. The most frequent sites of metastases are the liver and lungs. A new therapeutic approach is required to prevent tumour implantation of freely circulating tumour cells during and after surgery and to treat established metastases. The aim of this prospective study was to observe the influence of long-term intravenous taurolidine on the development of lung metastases after intravenous injection of colon adenocarcinoma cells. METHODS: Tumour cells (DHD/K12/TRb colon adenocarcinoma cell line, 1 x 10(6) cells) were injected into the right vena jugularis interna of BDIX rats. The animals (n=13) were randomised into three groups: group 1: tumour cell implantation without taurolidine application (control group); group 2: tumour cell implantation and simultaneous start of the taurolidine injection through osmotic pump, removal of the osmotic pump on day 7; group 3: tumour cell implantation on day 0 and start of the taurolidine injection through osmotic pump on day 14. RESULTS: In the taurolidine groups, the number and size of lung metastases were significantly lower compared to the control group (p=0.018; p=0.018 and p=0.036; p=0.018). Although the results of the intravenous long-term therapy with taurolidine in group 2 did not reach statistical significance in comparison with the results of group 3, a positive trend was revealed: The mean number of metastases in group 2 was 18.2 versus 28.2 in group 3. CONCLUSIONS: The application of taurolidine tends to prevent the development of lung metastases. Furthermore, taurolidine seems to reduce established lung metastases in this in vivo model. Taurolidine may offer additional therapeutic options in patients with colon adenocarcinoma.

Advanced glycation end products regulate extracellular matrix protein and protease expression by human glomerular mesangial cells

Advanced glycation end products (AGEs) may play a role in the pathogenesis of diabetic nephropathy, by modulating extracellular matrix turnover. AGEs are known to activate specific membrane receptors, including the receptor for AGE (RAGE). In the present study, we analyzed the various receptors for AGEs expressed by human mesangial cells and we studied the effects of glycated albumin and of carboxymethyl lysine on matrix protein and remodelling enzyme synthesis. Membrane RAGE expression was confirmed by FACS analysis. Microarray methods, RT-PCR, and Northern blot analysis were used to detect and confirm specific gene induction. Zymographic analysis and ELISA were used to measure the induction of tPA and PAI-1. We show herein that cultured human mesangial cells express AGE receptor type 1, type 2 and type 3 and RAGE. AGEs (200 microg/ml) induced at least a 2-fold increase in mRNA for 10 genes involved in ECM remodelling, including tPA, PAI-1 and TIMP-3. The increase in tPA synthesis was confirmed by fibrin zymography. The stimulation of PAI-1 synthesis was confirmed by ELISA. AGEs increased PAI-1 mRNA through a signalling pathway involving reactive oxygen species, the MAP kinases ERK-1/ERK-2 and the nuclear transcription factor NF-kappaB, but not AP-1. Carboxymethyl lysine (CML, 5 microM), which is a RAGE ligand, also stimulated PAI-1 synthesis by mesangial cells. In addition, a blocking anti-RAGE antibody partially inhibited the AGE-stimulated gene expression and decreased the PAI-1 accumulation induced by AGEs and by CML. Inhibition of AGE receptors or neutralization of the protease inhibitors TIMP-3 and PAI-1 could represent an important new therapeutic strategy for diabetic nephropathy.

Gas-phase Dissociation of homo-DNA Oligonucleotides

Synthetic modified oligonucleotides are of interest for diagnostic and therapeutic applications, as their biological stability, pairing selectivity, and binding strength can be considerably increased by the incorporation of unnatural structural elements. Homo-DNA is an oligonucleotide homologue based on dideoxy-hexopyranosyl sugar moieties, which follows the Watson-Crick A-T and G-C base pairing system, but does not hybridize with complementary natural DNA and RNA. Homo-DNA has found application as a bioorthogonal element in templated chemistry applications. The gas-phase dissociation of homo-DNA has been investigated by ESI-MS/MS and MALDI-MS/MS, and mechanistic aspects of its gas-phase dissociation are discussed. Experiments revealed a charge state dependent preference for the loss of nucleobases, which are released either as neutrals or as anions. In contrast to DNA, nucleobase loss from homo-DNA was found to be decoupled from backbone cleavage, thus resulting in stable products. This renders an additional stage of ion activation necessary in order to generate sequence-defining fragment ions. Upon MS(3) of the primary base-loss ion, homo-DNA was found to exhibit unspecific backbone dissociation resulting in a balanced distribution of all fragment ion series.

Future treatment strategies in ST-segment elevation myocardial infarction

Over the past five decades, management of acute ST-segment elevation myocardial infarction (STEMI) has evolved substantially. Current treatment encompasses a systematic chain of network activation, antithrombotic drugs, and rapid instigation of mechanical reperfusion, although pharmacoinvasive strategies remain relevant. Secondary prevention with drugs and lifestyle modifications completes the contemporary management package. Despite a tangible improvement in outcomes, STEMI remains a frequent cause of morbidity and mortality, justifying the quest to find new therapeutic avenues. Ways to reduce delays in doing coronary angioplasty after STEMI onset include early recognition of symptoms by patients and prehospital diagnosis by paramedics so that the emergency room can be bypassed in favour of direct admission to the catheterisation laboratory. Mechanical reperfusion can be optimised by improvements to stent design, whereas visualisation of infarct size has been improved by developments in cardiac MRI. Novel treatments to modulate the inflammatory component of atherosclerosis and the vulnerable plaque include use of bioresorbable vascular scaffolds and anti-proliferative drugs. Translational efforts to improve patients' outcomes after STEMI in relation to cardioprotection, cardiac remodelling, and regeneration are also being realised. This is the third in a Series of three papers about ST-segment elevation myocardial infarction.

Targeting the sphingosine kinase/sphingosine 1-phosphate pathway to treat chronic inflammatory kidney diseases

Chronic kidney diseases including glomerulonephritis are often accompanied by acute or chronic inflammation that leads to an increase in extracellular matrix (ECM) production and subsequent glomerulosclerosis. Glomerulonephritis is one of the leading causes for end-stage renal failure with high morbidity and mortality, and there are still only a limited number of drugs for treatment available. In this MiniReview, we discuss the possibility of targeting sphingolipids, specifically the sphingosine kinase 1 (SphK1) and sphingosine 1-phosphate (S1P) pathway, as new therapeutic strategy for the treatment of glomerulonephritis, as this pathway was demonstrated to be dysregulated under disease conditions. Sphingosine 1-phosphate is a multifunctional signalling molecule, which was shown to influence several hallmarks of glomerulonephritis including mesangial cell proliferation, renal inflammation and fibrosis. Most importantly, the site of action of S1P determines the final effect on disease progression. Concerning renal fibrosis, extracellular S1P acts pro-fibrotic via activation of cell surface S1P receptors, whereas intracellular S1P was shown to attenuate the fibrotic response. Interference with S1P signalling by treatment with FTY720, an S1P receptor modulator, resulted in beneficial effects in various animal models of chronic kidney diseases. Also, sonepcizumab, a monoclonal anti-S1P antibody that neutralizes extracellular S1P, and a S1P-degrading recombinant S1P lyase are promising new strategies for the treatment of glomerulonephritis. In summary, especially due to the bifunctionality of S1P, the SphK1/S1P pathway provides multiple target sites for the treatment of chronic kidney diseases.

Unique posttranslational modifications in eukaryotic translation factors and their roles in protozoan parasite viability and pathogenesis.

Protozoan parasites are one of the major causes of diseases worldwide. The vector transmitted parasites exhibit complex life cycles involving interactions between humans, protozoa, and arthropods. In order to adapt themselves to the changing microenvironments, they have to undergo complex morphological and metabolic changes. These changes can be brought about by expressing a new pool of proteins in the cell or by modifying the existing repertoire of proteins via posttranslational modifications (PTMs). PTMs involve covalent modification and processing of proteins thereby modulating their functions. Some of these changes may involve PTMs of parasite proteins to help the parasite survive within the host and the vector. Out of many PTMs known, three are unique since they occur only on single proteins: ethanolamine phosphoglycerol (EPG) glutamate, hypusine and diphthamide. These modifications occur on eukaryotic elongation factor 1A (eEF1A), eukaryotic initiation factor 5A (eIF5A) and eukaryotic elongation factor 2 (eEF2), respectively. Interestingly, the proteins carrying these unique modifications are all involved in the elongation steps of translation. Here we review these unique PTMs, which are well conserved in protozoan parasites, and discuss their roles in viability and pathogenesis of parasites. Characterization of these modifications and studying their roles in physiology as well as pathogenesis will provide new insights in parasite biology, which may also help in developing new therapeutic interventions.

Immunohistochemical evaluation of heat shock protein expression in normal canine nerve and peripheral nerve sheath tumours

Abnormal expression of heat shock proteins (HSPs) has been observed in many human neoplasms and such expression has prognostic, predictive and therapeutic implications. The aim of this study was to evaluate immunohistochemically the expression of HSP 27, HSP 32 and HSP 90 in normal canine peripheral nerves and in four benign and 15 malignant canine peripheral nerve sheath tumours (PNSTs). In normal nerve, all of the HSPs were detected in axons, epineurial fibroblasts and scattered Schwann cell bodies. Cytoplasmic expression of HSP 27 was more widespread and intense in benign PNSTs compared with malignant PNSTs (P <0.05). Widespread and intense nuclear expression of HSP 32 was also associated with benign tumours (P <0.01), while high HSP 90 immunoreactivity was detected in all tumours, suggesting that HSP 90 might represent a new therapeutic target.

Size-Dependent Uptake of Particles by Pulmonary Antigen-Presenting Cell Populations and Trafficking to Regional Lymph Nodes

The respiratory tract is an attractive target organ for novel diagnostic and therapeutic applications with nano-sized carriers, but their immune effects and interactions with key resident antigen-presenting cells (APCs) such as dendritic cells (DCs) and alveolar macrophages (AMs) in different anatomical compartments remain poorly understood. Polystyrene particles ranging from 20 nm to 1,000 nm were instilled intranasally in BALB/c mice, and their interactions with APC populations in airways, lung parenchyma, and lung-draining lymph nodes (LDLNs) were examined after 2 and 24 hours by flow cytometry and confocal microscopy. In the main conducting airways and lung parenchyma, DC subpopulations preferentially captured 20-nm particles, compared with 1,000-nm particles that were transported to the LDLNs by migratory CD11blow DCs and that were observed in close proximity to CD3+ T cells. Generally, the uptake of particles increased the expression of CD40 and CD86 in all DC populations, independent of particle size, whereas 20-nm particles induced enhanced antigen presentation to CD4+ T cells in LDLNs in vivo. Despite measurable uptake by DCs, the majority of particles were taken up by AMs, irrespective of size. Confocal microscopy and FACS analysis showed few particles in the main conducting airways, but a homogeneous distribution of all particle sizes was evident in the lung parenchyma, mostly confined to AMs. Particulate size as a key parameter determining uptake and trafficking therefore determines the fate of inhaled particulates, and this may have important consequences in the development of novel carriers for pulmonary diagnostic or therapeutic applications.